A pontoon is a flat-bottomed boat made of wood, waterproofed canvas, galvanized steel or aluminum, which is designed to support a structure on water. Military pontoons are used to build temporary pontoon bridges for river crossings, where permanent bridges are not available or have been destroyed in the conflict. Pontoons and bridging materials may be transported by artillery, pontoon or bridging trains of the army, using dedicated pontoon wagons. Military pontoon bridges differ from civilian floating bridges in that they use the smaller, lighter, and more mobile military pontoons, rather than heavy river barges.
Several pontoons may be lashed together to ferry troops and vehicles across the river, until a pontoon bridge has been completed.
French engineers building a pontoon bridge across the Danube at Sonderheim on 13 August 1704, during the Battle of Blenheim. The bridge was not completed in time, and many retreating French soldiers drowned when they attempted to evade capture by swimming across the river. The scene is a section of the diorama of the Battle of Blenheim displayed at the Heimatmuseum in Höchstädt an der Donau.
Scale modelling instructions for pontoons may be found in the Miniatures Forum.